The reaction of the complex [(dippe)NiH]2 (1) with a variety alkyl cyanides afforded nickel(0) compounds type [(dippe)Ni(η2-RCN)], where R = Me, Et, Pr, iPr, tBu, cyclopropyl, cyclobutyl, adamantyl (2−9, respectively). When 2−9 were warmed to yield oxidative addition products, thermal proceeded only in case 2 produce [(dippe)Ni(Me)(CN)] (10). Photochemical activation did products from 2−8, which rapidly evolved β-elimination organic moiety most cases and formation [(dippe)Ni(CN)2] (11)....

We report a nickel(0)-catalyzed direct transfer hydrogenation (TH) of variety alkyl-aryl, diaryl, and aliphatic ketones with ethanol. This protocol implies reaction in which primary alcohol serves as hydrogen atom source solvent one-pot without any added base. The catalytic activity the nickel complex [(dcype)Ni(COD)] (e) (dcype: 1,2-bis(dicyclohexyl-phosphine)ethane, COD: 1,5-cyclooctadiene), towards carbonyl compounds using ethanol donor was assessed broad scope ketones, giving excellent...

Homogeneous catalytic hydrodefluorination (HDF) of fluoroaromatics under thermal conditions was achieved using nickel(0) compounds the type [(dippe)Ni(η2-C6F6-nHn)] where n = 0–2, as precursors. These complexes were prepared in situ by reacting compound [(dippe)Ni(μ-H)]2 with respective fluoroaromatic substrate. HDF seems to occur homogeneously, tested mercury drop experiments, producing hydrodefluorinated products. However, despite previous findings other groups, we found that these...

The homogeneous catalytic hydration of benzo- and acetonitrile under thermal conditions was achieved using nickel(0) compounds the type [(dippe)Ni(η2-NCR)] with R=phenyl or methyl (compounds 1 2, respectively), as specific starting intermediates. Alternatively, complexes may be prepared in situ by direct reaction precursor [(dippe)NiH]2 (3) respective nitrile. Hydration appears to occur homogeneously, tested mercury drop experiments, producing benzamide acetamide, respectively. Addition...

The nickel(0) fragment [(P−P)Ni], where (P−P) = dcype (1,2-bis(dicyclohexylphosphino)ethane) or dtbpe (1,2-bis(di-tert-butylphosphino)ethane), reacts with the cyano-olefins involved in isomerization process of 2-methyl-3-butenenitrile (2M3BN), producing corresponding complex [(P−P)Ni(η2-C,C-cyano-olefin)]. In case 2M3BN and 3-pentenenitrile (3PN), π-methylallyl metal was observed solution. All intermediates catalytic cycle were detected characterized by heteronuclear NMR spectroscopy; some...

Abstract The use of low‐valent nickel complexes in homogeneous catalytic reactions some industrially relevant transformations that employ low reactive substrates are presented.

Nickel(0) catalysts were used to produce substituted imidazoles in good high yields using benzonitrile, p-substituted benzonitriles and 4-cyanopyridine as starting materials.

The catalytic reduction of phthalimide was achieved using nickel catalysts. use amounts (20% mol) [Ni(COD)2] or [(dippe)Ni(μ-H)]2 (1) allowed the monoreduction to yield isoindolinone and benzamide, at 140–180 °C 750 psi H2. When N–H moiety protected with a trimethylsilyl group, both C═O groups were reduced (trimethylsilyl)isoindoline. However, when methyl used as protecting aromatic ring reduced, rather similar reaction conditions, due formation 5 Å (average) nanoparticles.

Catalytic amounts (1−0.1 mol %) of nickel and platinum compounds in 0, I, II oxidation states containing mono- diphosphines ligands, conjunction with alkyl Grignard reagents, promoted the desulfurization dibenzothiophene (DBT), 4-methyldibenzothiophene (4-MeDBT), 4,6-dimethyldibenzothiophene (4,6-Me2DBT), to produce corresponding substituted unsubstituted biphenyls. It was also observed that use polar solvents such as THF yielded thiols, while nonpolar allowed complete these substrates.

The reaction of [Pt(PEt3)3], 1, with 3-methylbenzothiophene and 2-methylbenzothiophene afforded the thiaplatinacycles [(Et3P)2Pt(C,S-C9H8S)], 3 4, respectively. In formation both complexes (Et3P)2Pt has inserted into C−S bond to vinylic carbon. Complex 4 rearranges in solution a dimeric thiaplatinacycle, 5, which platinum moved from lying between aromatic bond. Reaction 1 4-methyldibenzothiophene gave mixture isomeric [(Et3P)2Pt(C,S-C13H10S)], 6 7. 4,6-dimethyldibenzothiophene containing...

Catalytic amounts of the compounds [(dippe)NiH]2 (1), [(dcpe)NiH]2 (2), and [Ni(PEt3)4] (3) (1−0.1 mol %) with alkyl Grignard reagents promoted desulfurization dibenzothiophene, 4-methyldibenzothiophene, 4,6-dimethyldibenzothiophene, to produce corresponding biphenyls (90−100%) in toluene or mixtures thiols favored THF. Also, thianickelacycle [(dippe)Ni(η2-C,S-C12H8)] (4) was used as a catalyst precursor test its participation an active intermediary catalytic cycle.

The reactions of [M(PEt3)3] (M = Pt (1), Pd (2), Ni (3)) with 3-chlorothiophene, 2-chlorothiophene, 3-nitrothiophene, 2-nitrothiophene, 2-methoxythiophene, 3-methoxythiophene, 2-acetylthiophene, and 3-acetylthiophene afforded thiaplatinacycles the type [(Et3P)2M(C,S-C4H3RS)], (for M Pt, R Cl (4 5), NO2 (6 7), MeO (8 9), Ac (10 11); for Pd, (12 13), (14), (15 16), (17 18), Ni, (19)). When 3 2-chlorothiophene were reacted, another compound resulting from oxidative addition C−Cl bond could be...

The reaction of dibenzothiophene (DBT) with [Ru3(CO)12] in heptane affords the dinuclear complex [Ru2(C12H8)(μ-CO)(CO)5], derived from a double C−S bond activation−desulfurization process. this H2 under very mild conditions leads to release biphenyl.

Reaction of the thiaplatinacyle [(Et3P)2Pt(C12H8S-C,S)] (3; derived from reaction [Pt(Et3P)3] and dibenzothiophene (DBT)) with HCl gives largely 2-phenylthiophenol a small amount DBT. The thiaplatinacycle [(Et3P)2Pt(C8H6S-C,S)] (2; benzothiophene (BT)) undergoes to give 2,3-dihydrobenzothiophene (22%), 2-vinylthiophenol, BT, while [(Et3P)2Pt(C4H4S-C,S)] (1; thiophene) regenerates thiophene HCl; in each case metal is found as [(Et3P)2PtCl2]. In contrast all thiaplatinacycles react very...

The synthesis of nickel(0) complexes usually requires the employment strong reducing agents, including powerful hydride donors such as LiHBEt3, LiAlH4, and DIBAL-H. Herein, we have reduced Ni(II) complex [(dippe)NiCl2] (1a) at room temperature by using KOH in aqueous media to yield low-valent [Ni(dippe)2] (4a) main product, along with formation dippeO2. In order gain some insight into reaction mechanism, a series intermediates were isolated characterized different stages. As result, both...

A one pot methodology using simple imines allowed the formation of N-substituted imidazoles and imidazolines.

We report a well-defined homogeneous nickel-based catalyst using the complex [dippeNi(COD)] (dippe=1,2-bis(diisopropyl phosphino)ethane) as catalytic precursor with high activity in hydrogenation of levulinic acid (LVA) to yield γ-valerolactone (GVL) under relatively mild conditions (4 h, 120 °C); formic (FA) is transfer agent dehydrogenation-hydrogenation process. Under optimized conditions, GVL was obtained excellent (>99 %) and selectivity %). The Ni-catalyst assessed LVA variety primary...

The reactivity of Grignard reagents in the presence nickel catalysts is known to be highly efficient deoxydesulfurization dibenzothiophene sulfone (DBTO2), 4-methyldibenzothiophene (4-MeDBTO2), and 4,6-dimethyldibenzothiophene (4,6-Me2DBTO2), yield sulfur-free biphenyls via cross-coupling reactions. However, mechanistic details involved process remained unknown. In this report [(dippe)Pt(μ-H)]2 with DBTO2 turned out catalytically less compared [(dippe)Ni(μ-H)]2, but first allowed isolation...

A new mechanistic proposal based in theoretical and experimental evidence invoking the participation of water is presented.

The first example of a homogeneous hydration aromatic nitriles catalyzed by manganese molecular compounds is reported.